• Journal of the Korean Institute of Telematics and Electronics S
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• v.36S no.6
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• pp.17-29
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• 1999

In this paper, the prioritized queueing handoff scheme in CDMA (Code Division Multiple Access) cellular system is proposed. Also, the analytical survey for the proposed scheme is carried out, and the performance of this scheme is compared with that of non prioritized scheme and FIFO (First In First Out) queue scheme by computer simulation. The handoff region is defined as the time between the handoff treshold and the receiver threshold, and it is used for the maximum queue waiting time in the proposed scheme. The handoff and the receiver thresholds are defined as rewpectively: 1) the time that the Pilot Strength Measurement Message in the neighbor in the neighbor cell is received to the BS (Base Station) under the T_ADD threshold; and 2) the time that the T_DROP timer is expired and the Pilot Strength Measurement Message in the current cell is received to the BS under the T_DROP threshold. The performance metrics for analyzing the proposed scheme are : 1) probability of forced termination; 2) probability of call blocking; 3) ratio of carried traffic to total offered load; 4) average queue size; 5) average handoff delay time in queue. The simulation results show that the proposed scheme maintains high performance for handoff requests at a small penalty in total system capacity.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.10 no.3
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• pp.479-485
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• 2006

The double gate(DG) MOSFET is a promising candidate to further extend the CMOS scaling and provide better control of short channel effect(SCE). DGMOSFETs, having ultra thin undoped Si channel for SCEs control, ale being validated for sub-20nm scaling. A novel analytical transport model for the subthreshold mode of DGMOSFETs is proposed in this paper. The model enables analysis of short channel effect such as the subthreshold swing(SS), the threshold voltage roil-off$({\Delta}V_{th})$ and the drain induced barrier lowering(DIBL). The proposed model includes the effects of thermionic emission and quantum tunneling of carriers through the source-drain barrier. An approximative solution of the 2D Poisson equation is used for the distribution of electric potential, and Wentzel-Kramers-Brillouin approximation is used for the tunneling probability. The new model is used to investigate the subthreshold characteristics of a double gate MOSFET having the gate length in the nanometer range $(5-20{\sim}nm)$ with ultra thin gate oxide and channel thickness. The model is verified by comparing the subthreshold swing and the threshold voltage roll-off with 2D numerical simulations. The proposed model is used to design contours for gate length, channel thickness, and gate oxide thickness.

• Computers and Concrete
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• v.5 no.4
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• pp.375-388
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• 2008

Crack opening governs many transfer properties that play a pivotal role in durability analyses. Instead of trying to combine continuum and discrete models in computational analyses, it would be attractive to derive from the continuum approach an estimate of crack opening, without considering the explicit description of a discontinuous displacement field in the computational model. This is the prime objective of this contribution. The derivation is based on the comparison between two continuous variables: the distribution if the effective non local strain that controls damage and an analytical distribution of the effective non local variable that derives from a strong discontinuity analysis. Close to complete failure, these distributions should be very close to each other. Their comparison provides two quantities: the displacement jump across the crack [U] and the distance between the two profiles. This distance is an error indicator defining how close the damage distribution is from that corresponding to a crack surrounded by a fracture process zone. It may subsequently serve in continuous/discrete models in order to define the threshold below which the continuum approach is close enough to the discrete one in order to switch descriptions. The estimation of the crack opening is illustrated on a one-dimensional example and the error between the profiles issued from discontinuous and FE analyses is found to be of a few percents close to complete failure.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.40 no.6
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• pp.1114-1116
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• 2015

In this paper, we propose a load distribution scheme in SDN utilizing load redirection, enabling incoming messages to be migrated to another controller. Specifically, when the capacity of a controller reaches a threshold, the controller makes incoming packets be migrated to a less-loaded controller to prevent them from being blocked. Analytical result shows that our scheme has lower blocking probability than the conventional scheme.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.13 no.4
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• pp.747-752
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• 2009

Three dimensional(3D) Poisson's equation is used to calculate the potential variation for FinFET in the channel to analyze subthreshold current and short channel effect(SCE). The analytical model has been presented to lessen calculating time and understand the relationship of parameters. The accuracy of this model has been verified by the data from 3D numerical device simulator and variation for dimension parameters has been explained. The model has been developed to obtain channel potential of FinFET according to channel doping and to calculate subthreshold current and threshold voltage.

• Journal of information and communication convergence engineering
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• v.16 no.1
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• pp.43-47
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• 2018

The existing modeling of avalanche dominated breakdown in double gate MOSFETs (DGMOSFETs) is not relevant for 10 nm gate lengths, because the avalanche mechanism does not occur when the channel length approaches the carrier scattering length. This paper focuses on the punch through mechanism to analyze the breakdown characteristics in 10 nm DGMOSFETs. The analysis is based on an analytical model for the thermionic-emission and tunneling currents, which is based on two-dimensional distributions of the electric potential, obtained from the Poisson equation, and the Wentzel-Kramers-Brillouin (WKB) approximation for the tunneling probability. The analysis shows that corresponding flat-band-voltage for fixed threshold voltage has a significant impact on the breakdown voltage. To investigate ambiguousness of number of dopants in channel, we compared breakdown voltages of high doping and undoped DGMOSFET and show undoped DGMOSFET is more realistic due to simple flat-band-voltage shift. Given that the flat-band-voltage is a process dependent parameter, the new model can be used to quantify the impact of process-parameter fluctuations on the breakdown voltage.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2008.10a
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• pp.579-582
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• 2008

Three dimensional(3D) Poisson's equation is used to calculate the potential variation in the channel to analyze subthreshold current and short channel effect(SCE). The analytical model has been presented to lessen calculating time and understand the relationship of parameters. The accuracy of this model has been verified by the data from 3D numerical device simulator and variation for dimension and process parameters has been explained. The model has been developed to obtain channel potential of FinFET according to channel doping and to calculate subthreshold current and threshold voltage.

• International Journal of Aeronautical and Space Sciences
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• v.7 no.1
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• pp.13-26
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• 2006

When the stagnation temperature of a perfect gas increases, the specific heat for constant pressure and ratio of the specefic heats do not remain constant any more and start to vary with this temperature. The gas remains perfect: its state equation remains always valid, with exception that it will be named by calorically imperfect gas. The aim of this research is to develop the relations of the necessary thermodynamics and geometrical ratios. and to study the supersonic flow at high temperature. lower than the threshold of dissociation. The results are found by the resolution of nonlinear algebraic equations and integration of complex analytical functions where the exact calculation is impossible. The dichotomy method is used to solve the nonlinear equation. and the Simpson algorithm for the numerical integration of the found integrals. A condensation of the nodes is used. Since. the functions to be integrated have a high gradient at the extremity of the interval of integration. The comparison is made with the calorifcally perfect gas to determine the error made by this last. The application is made for the air in a supersonic nozzle.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.65 no.5
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• pp.785-793
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• 2016

This paper analyzes an LCL-type isolated dc-dc converter operating for constant output voltage in the continuous conduction mode(CCM) with resistances of parasitic losses-static drain-source on resistance of power switch, ESR of resonant network(L-C-L)-using a high loaded quality factor Q assumptions and fourier series techniques. Simple analytical expressions for performance characteristics are derived under steady-state conditions for designing and understanding the behavior of the proposed converter. The voltage-driven rectifier is analyzed, taking into account the diode threshold voltage and the diode forward resistance. Experimental results measured for a proposed converter at low input voltage and various load resistances show agreement to the theoretical performance predicted by the analysis within maximum 4% error. Especially in the case of low output voltages and large loads, It is been observed that introduction of both rectifier and the parasitic components of converter had considerable effect on the performance.

• Proceedings of the Ginseng society Conference
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• 1978.09a
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• pp.85-92
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• 1978

The aim of the double blind test was to assess the prophylactic and therapeutic efficacy of the preparation GINSANA, containing the standardized ginseng extract PHARMATON G115,. The determination was carried out with special emphasis on the following features : general physical condition, physical performance, mental performance, enjoyment of life/mood, concentration and memory, as well as sleeping habits. Sixty test persons took part in the study, men and women between the ages of 22 and 80. The 90-day test was carried out in the form of a double blind experiment. Experimental measurements were made and the persons were also questioned. The reaction time, the optical merging threshold, the coordination of both hands and the recovery quotients, as well as the recovery rates were analyzed. The results for the serum group were clearly better than those for the placebo group, particularly for the characteristics: general physical condition, physical performance and sleeping habits. The results of the test methods used, especially with regard to the reaction time, the coordination of both hands, the recovery quotient and the recovery period, permit the following conclusion to be drawn: when administered for several weeks, GINSANA has a positive action, in the sense of an activation of the entire personality by the ginseng glycosides contained in the standardized Extracts G115.